Magnetoresistance and Ferromagnetism in Disordered LaCu0.5Mn0.5O3 Perovskite

Magnetoresistance (MR) in half doped copper LaCu0.5Mn0.5O3 manganese related perovskite, synthesized by means of a soft chemistry pathway, is reported. Characterization by means of Rietveld refinement from powder X-ray diffraction data, SAED, HREM, and EELS indicates a random occupation of Cu2+ and Mn4+ at the octahedral sites of an orthorhombic perovskite lattice. This disordered situation is in agreement to the absence of charge ordering. LaCu0.5Mn0.5O3 exhibits antiferromagnetic behavior related to Mn4+–O–Mn4+ and Cu2+–O–Cu2+ interactions. Ferromagnetic interactions are also evident as a consequence of a disordered arrangement of Cu2+ and Mn4+ over the octahedral sites, being the coexistence of these ferromagnetic superexchange interactions related to the observed MR behavior at low temperature.